A mysterious illness has claimed the lives of tens of thousands of starfish on North America's west coast, and its symptoms are horrifying. Dubbed "sea star wasting syndrome," the arms of an infected individual will twist into knots, develop lesions, and finally crawl away in opposite directions until they tear away from its body, allowing its insides to spill out.

Researchers still aren't sure how the disease spreads, let alone where it comes from. What they do know is that sea stars occupy a pivotal niche in ocean ecosystems, and large-scale die outs are almost certainly a very bad sign.